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Key message: We mapped Ryd4Hb in a 66.5 kbp interval in barley and dissociated it from a sublethality factor. These results will enable a targeted selection of the resistance in barley breeding. Virus diseases are causing high yield losses in crops worldwide. The Barley yellow dwarf virus (BYDV) complex is responsible for one of the most widespread and economically important viral diseases of cereals. While no gene conferring complete resistance (immunity) has been uncovered in the primary gene pool of barley, sources of resistance were searched and identified in the wild relative Hordeum bulbosum, representing the secondary gene pool of barley. One such locus, Ryd4Hb, has been previously introgressed into barley, and was allocated to chromosome 3H, but is tightly linked to a sublethality factor that prevents the incorporation and utilization of Ryd4Hb in barley varieties. To solve this problem, we fine-mapped Ryd4Hb and separated it from this negative factor. We narrowed the Ryd4Hb locus to a corresponding 66.5 kbp physical interval in the barley ‘Morex’ reference genome. The region comprises a gene from the nucleotide-binding and leucine-rich repeat immune receptor family, typical of dominant virus resistance genes. The closest homolog to this Ryd4Hb candidate gene is the wheat Sr35 stem rust resistance gene. In addition to the fine mapping, we reduced the interval bearing the sublethality factor to 600 kbp in barley. Aphid feeding experiments demonstrated that Ryd4Hb provides a resistance to BYDV rather than to its vector. The presented results, including the high-throughput molecular markers, will permit a more targeted selection of the resistance in breeding, enabling the use of Ryd4Hb in barley varieties. [ABSTRACT FROM AUTHOR]

Abstract: Narrow‐leafed lupin (NLL) is a source of protein and fibre with exceptional functional properties useful for a variety of purposes. In adapted NLL germplasm selected for low alkaloid contents, the genetic base is narrow, thus limiting fast breeding progress. In an EMS‐based mutagenesis programme, we have treated 40,000 seeds of cv. ‘Boruta’ and obtained a variety of phenotypic mutant lines expressing novel growth types with altered plant height and/or branching. In 3‐year field trials at two locations, three of these lines exhibited significantly improved grain yield components compared to the cv. ‘Boruta’. Growth types of these promising lines were shown to be inherited in a monogenic recessive manner and should, thus, be easily fixable by breeding. [ABSTRACT FROM AUTHOR]

Barley yellow dwarf virus (BYDV) causes high yield losses in most of the major cereal crops worldwide. A source of very effective resistance was detected within the tetraploid wild species of Hordeum bulbosum. Interspecific crosses between a resistant H. bulbosum accession and H. vulgare cv. ‘Igri’ were performed to transfer this resistance into cultivated barley. Backcrosses to H. vulgare resulted in offspring which carried a single subterminal introgression of H. bulbosum chromatin on barley chromosome 3HL and proved to be fully resistant to BYDV-PAV, as inferred by ELISA values of zero or close to zero and lack of BYDV symptoms. Genetic analysis indicated a dominant inheritance of the BYDV-PAV resistance factor, which we propose to denote Ryd4 Hb . The identity and effect of Ryd4 Hb are discussed in relation to other known genes for BYDV resistance or tolerance, as well as the relevance of this gene for resistance breeding in barley. [ABSTRACT FROM AUTHOR]

The article presents a study on the transcriptome-based mapping of anthracnose resistance gene in yellow lupin. It discusses the disappearance of the yellow lupin from the fields in Germany due to high susceptibility against the fungal disease anthracnosis caused by pathogen Colletotrichum lupini., along with development of several marker techniques to eliminate it.

The article examines stem-rust resistance in perennial ryegrass (Lolium perenne), one of the cool-season grass species in temperate zones. It is said that the obligate biotrophic pathogen Puccinia graminis f.sp. graminicola cause stem rust that affect seed production of ryegrass. A leaf segment test screened a perennial ryegrass mapping population segregating for stem-rust resistance.